In LTE (Long Term Evolution) standardized in 3GPP (3rd Generation Partnership Project) which is a group aiming to standardize a radio communication system, a technology called SON (Self Organizing Network) is employed. According to the SON, it is expected to automatize the installation or maintenance of a radio base station without measurement or setting in a field by manpower (for example, see Non Patent Literature 1).
In the SON, in order to equalize a load between radio base stations (called “eNB” in the 3GPP), there has been proposed a technique of adjusting a coverage on the basis of load information transmitted and received between the radio base stations. In the technique of adjusting the coverage, at the time of handover, when there are a radio base station having a high load and a radio base station having a low load, a radio terminal connected to the radio base station having a high load is handed over to the radio base station having a low load.